Suit heater



Sept. 24, 1968 w, SHWERS ET AL 3,402,709

SUIT HEATER Filed June 27, 1967 INVENTORS Rufus W. Shivers Edgggrd L.Beckmon United States Patent 0 3,402,709 SUIT HEATER Rufus W. Shivers,Washington, D.C., and Edward L.

Beckman, Gaithersburg, Md assignors to the United States of America asrepresented by the United States Atomic Energy Commission Filed June 27,1967, Ser. No. 649,362 4 Claims. (Cl. 126-204) ABSTRACT OF THEDISCLOSURE Apparatus for heating garments such as suits for swimmers orastronauts who may be subjected to cold water or space environments,which utilizes a radioisotope heat source to furnish heat to fluid thatis pumped through conduits or passageways of the apparatus and garment,and which includes means for selectively bypassing fluid so as to varythe temperature of fluid pumped through the garment passageways.

Background of invention One of the hazards to swimmers or astronauts islow tempenatures. For example, even tropical waters do not match thehuman body temperature of about 98.6 F. (37 0). Additionally, thethermal gradient of waters drops with increasing depth. Most deep divingis performed in ambient temperatures 25 to 50 below normal humantemperature. The result is that, as a function of exposure time, bodytemperature gradually decreases. Physiologically, the importanttemperature measurement is the core temperature (the inner bodytemperature measured at about heart level). Body protective measurementsare designed to protect this core temperature. If the core temperaturebegins to diminish the effectiveness of body function is affected andhuman performance deteriorates. At first the core temperature dropsgradually but more rapidly later, as a function related to watertemperature and time.

In deep diving operations a helium oxygen gas is generally used. Heliumis a light gas and minimizes or overcomes the problems of ordinary airbecoming very dense under pressures greater than 100 feet. It alsominimizes or eliminates the narcotic effect of nitrogen. However, it isa poor insulator and causes personnel exposed to low temperatures foundat deep depths to lose body heat faster.

The human body responds to lowered core temperature by a shivering andteeth chattering response. Numbing cold sets in. A diver with selfcontained underwater breathing apparatus (SCUBA) having such response isineffective and in danger. When the shivering and teeth chattering stateis reached, the diver-swimmer is no longer capable of holding a SCUBAmouthpiece in place or of performing useful work.

Protective suits made of foam rubber are good for relatively shortperiods of time of about 2 to 3 hours in the water. However, the colderthe water, the shorter this effective period will be. Additionally, thefoam is compressible and, therefore, less insulative with increasingdepth.

Heated suits utilizing various power sources are required for longperiods of time. There exist at present electrically heated suits, whichrequire approximately 25 pounds of batteries and which last 1 to 3 hoursbefore recharging, but these are bulky and expensive to operate.

The most desirable solution appears to be a circulating hot water systemthat an occupant or wearer plugs into and out of. The swimmer would weara suit embedded with vein-like tubes or passageways, which would carry'ice and through which would circulate the heated water (similar suitsare used by astronauts, aviators and racing car drivers to keep cool byuse of a coolant fluid in the tubes).

In the case of the swimmer or diver heat to be supplied to transferfluid in the suit passageways would by this invention come from aradioisotope backpack heater capable of furnishing around 300 to 400thermal watts for maintaining body temperature. In addition to use forunderwater swimmers, the unit may be used by downed pilots or suits forland operations in the Arctic and Antarctic.

Summary of invention With the foregoing in mind, it is an object of thisinvention to provide a compact, relatively light weight apparatus ordevice for furnishing heated fluid to a garment.

Another object of this invention is to provide an apparatus forsupplying heated fluid to a garment that may be operated for relativelylong periods of time without need of rejuvenation.

A further object of this invention is to provide an apparatus capable offurnishing ample heat output over relatively long periods of time.

Various other objects and advantages will appear from the followingdescription of the invention and its features.

The invention comprises container means which houses a radioactiveisotope heat source or capsule within shielding with heat transfer fluidbeing pumped over the heat source and through passageways of a garment;selectively controllable fluid bypassing means is provided to facilitatecontrolling temperature of fluid to the garment.

Description of the drawings Various embodiments and features of theinvention are shown in the accompanying drawing wherein:

FIG. 1 is a more or less diagrammatic sectional view of the invention;

FIG. 2 is a view taken generally along line 22 of FIG. 1;

FIG. 3 is a view showing a heat releasing feature;

FIG. 4 is a longitudinal sectional view showing various improved ormodified features; and

FIG. 5 is a view taken generally along line 5--5 of FIG. 4.

Detailed description As shown in FIGS. 1 and 2, an appropriate number ofradioisotope heat sources or capsules 1 are housed within an outerprotective housing or container 2 through which a heat transfer fluid 4,which may be a gas or liquid such as water but which is preferably thelatter, is moved by any suitable pump 5. The fluid moves freely over theheat sources so as to pick up heat therefrom and emerges from theinterior of the container 2 through outlet conduits 7, throughcommercially available quick connectdisconnect couplings 9, and thenceflexible, vein-like conduits or passageways 8 of a garment 10, which maybe a swim suit or astronaut suit. The passageways and manifolds of thegarment 10 may be of any apropriate configuration and may connect in anysuitable manner to the above-rnentioned fluid delivery conduit orpassageway 7. Upon emerging from garment 10 the fluid is shown to flowthrough passageway 11 back into the container 2.

The container 2 is preferably provided with heat or thermal insulationor shielding 14 and may also embody radioactivity radiation shielding 16of lead, hydrogenous material, or other suitable materials. While theradiation shielding is indicated in FIGS. 1 and 2 as being carried bythe container 2 it will be clear that it may directly enclose or besecured to the various individual radioisotope heater units 1. In someinstances the radiation shielding may be omitted as the water in which aswimmer is located provides at least partial radiation shielding.

The pump 5 and its driving motor which move fluid through the variousconduits or passageways may be of any appropriate type, e.g., acommercially available electrically driven (constant or variable speed)one as available from Normalair, Ltd. and the motor may be driven by anysuitable power system, e.g., one or more batteries 17 such assilver-Zinc rechargeable types commercially available from YardneyElectric Corporation or others.

A hand operated valve 19 may be provided in the conduit 7 forselectively controlling the quantity of fluid passing through thatconduit and the garment passageways 8 and thereby controlling thequantity of heat which is received by the diver or astronaut. Acommercially available needle or other valve may be utilized, with thecontainer handle being readily accessible to and actuable by the wearer.To further facilitate desired control of the fluid and circulation aboutthe heat sources 1, there is provided a by-pass conduit 20 and a similarneedle or other type valve 21 therein for transferring fluid from theoutlet side of the pump 5 and returning it to the container 2, prior tothe thus bypassed fluid reaching the passageways of the garment 10.

While three radioisotope heat or fuel capsules are indicated in FIG. 1any appropriate number may be employed, depending upon the desiredthermal output. Preferable radioisotopes are alpha or beta emitters withlow radiation emissions. Plutonium 238 or an alloy thereof issatisfactory. Other isotopes which may be employed are polonium 210,promethium 147, curium 242, curium 244, americium 241, thulium 170,thulium 171, thallium 204, cesium 137, cerium 144, strontium 90, etc. Ingeneral, about 300 to 400 thermal watts output is desirable forunderwater swimmers at underwater temperature of around 45 F.;additional heat may be desirable for astronauts in the cold of outerspace or downed pilots in frozen areas.

It may be deemed desirable to provide offset conduit arrangements 23 andradioactivity shielding 24 adjacent portions where conduits enter oremerge, as indicated in FIGS. 1 and 2.

In some instances it may be desirable to further facilitate release ofheat from the apparatus and in FIG. 3 this is shown provided by louversor doors 28 supported in suitable manner on pins or hinges 29 at a sideor end wall 30 of the container, the louvers or doors being dis posedwithin opening 31 in the container wall. Portions of the insulation 14may be carried by the louvers 28 so as to expose the inner radioactivityshield or other innermost wall to the cold exterior sea water. Theswimmer or astronaut may selectively open or close the louvers torelease excess heat.

In FIGS. 4 and 5 there are shown various improvement or modifiedfeatures, wherein radioisotope fuel cells 01 capsules 35 are housedwithin a plurality of containers 36 and 37 and carried by holding means38 shown of generally tubular exterior configuration. The outercontainer 36 and additional or intermediate container 37 cooperate toform an intermediate evacuated or evacuable volume 40 (to reduce heatloss through the walls), being closed at their respective ends by outerend cap 41 and additional end cap 42. It will be noted that the latterend caps are bowed in opposite directions so as to provide greaterstrength against collapse when the volume 40 is evacuated. Additionally,the surfaces of these cylinders may be polished so as to furtherminimize heat loss.

The holding means or further container 38 is retained in position andspaced from the walls of the intermediate container 37 bycircumferentially spaced elongated wire wedging members 44 so as toprovide space between these two containers for passage of fluidtherebetween and the radioisotope fuel or heat capsules are shownmaintained in position within the holding means by longitudinalllyspaced capsule support members 46. The support members 46, which may bewelded or otherwise retained in position, carry the capsules inapertures 47 and are also provided with apertures 45 throughout theirareas for freely passing fluid flow therethrough, as well as with acentrally disposed aperture for receiving portions of a hot waterconduit or pipe 48 that will be more particularly referred to later.

The concentric containers 36, 37, and holding means 38, end caps 41 and42, capsule support members 46, and spacer wires 44 may be of anodizedaluminum, or any other suitable materials and the end caps 41 and 42 maybe joined or welded to their respective cylinders in any suitablemanner.

The outer and additional conatiners may be positioned and securedtogether by end or top cap 50 shown threaded at 49 to the outercontainer 36, with an inwardly extending flange 51 hearing against anend shoulder 52 of the additional container 37 so as to force the latterfirmly into engagement with an O-ring or spacer 53 of Plexiglas(polymerized methylmethacrylate), Teflon (polytetrafluoroethylene), orother suitable material. The spacer 53 rests in turn against inwardlyextending shoulder or ledge 54 of the outer container 36 and not onlyforms a secure vacuum tight seal between the outer and additionalcontainers but also provides a thermal insulation between these twocontainers.

The end or top cap 50 has an enlarged boss 58 which supports thepenetrating cold water inlet sleeve 61 and through the latter extendsthe hot water outlet tube 48, the latter extending through the centralapertures of the fuel cell supporting members 46 and terminatingadjacent but spaced from the end cap 42.

Cold water from a conduit may enter the cold Water inlet member 64 andemerge therefrom into the annular cold water space 65. The cold watersleeve is sealed or closed adjacent its end portions to hot Water sleeve48 by cap members 66 and hence the entering cold water emerges from thesleeve 61 through apertures 68 at inwardly disposed portions of thesleeve, thence flowing through the annular space intermediate theexterior of the innermost container 38 and adjacent wall of container37, as well as through apertures in the integral supporting andpositioning flange 63 of the hot water tube 48 and the various openingsin the fuel cell support members 46. In thus flowing through the notedopenings and spaces the fluid picks up heat given off by the fuel cellunits. After flowing in heat-removing contact with the fuel cell unitsand portions of the support means or container 38 the heated fluidenters the upper or inlet end 48A of the hot water tube 48 and flowstherethrough, at a speed of around an inch or two per second, enteringupon its emergence from the tube 48 (at a temperature in theneighborhood of F. to F.) the appropriate tubing which leads toward agarment 10 that is to be heated.

The end or top cap member 50 may be of anodized aluminum, as may be thecold water sleeve 61 and the cold water inlet member 64. The hot watertube 48 and its integral supporting flange portion 63 may be of plasticsuch as polyvinyl chloride as such material provides a thermalinsulation between the hot and cold flowing streams of fluid. The endmember or cap 66 of the cold water sleeve 61 may be cemented intoposition on both the cold water sleeve and the hot water tube by anysuitable adhesive material and the cold water sleeve may be similarlycemented together with the cold water inlet member 64 and boss 58 of theend member 50.

With the construction shown in FIG. 4 fluid bypassed by and emergingfrom a bypass valve does not directly re-enter the containers butinstead first passes through a bypass heat exchanger coiled portion 70,of aluminum, copper, brass or any other suitable material shown coiledabout the exterior of the outer container 36 and thence returns via aconduit to the cold water inlet member 64 as indicated and to theinterior of a container. If a diver becomes too warm he can bypass someof the hot water through the bypass coil by opening the bypass needlevalve, so that hot water circulates through the coil and its temperatureapproaches that of the surrounding ocean, after which it re-enters themain flow of water.

If considered desirable, the heat sources can be removed by unscrewingthe top cap 50.

As shown in FIGS. 4 and 5, four heat sources are employed, each of whichmay incorporate plutonium 238 and supply approximately 105 watts ofthermal power. The heat sources may be stored apart from the device whennot in use and may be installed just prior to a mission after theswimmer is suited. Also, no lead radioactivity shielding is shown in theFIG. 4 apparatus as such may be dispensed with in some instances.

An idea as to compactness of the heater assembly of FIG. 4 may beobtained from its dimensions of approximately 12 to 13 inches long and 4inches in diameter, with a weight of around 20 pounds.

The described apparatus which furnishes heat for a garment need not, ofcourse, be permanently assembled with the flexible tubing of suchgarment but may be in the form of a backpack or other unit which may bereadily assembled or removed therefrom by means of suitable quickdisconnect couplings 9.

It will be understood that various changes may be made by those skilledin the art within the principles and scope of the invention as expressedin the appended claims.

What is claimed is:

1. For use with a garment to be heated through a fluid passagewaytherein, apparatus to supply heated fluid to said passageway, saidapparatus comprising the combination of a container filled with a heattransfer fluid, a plurality of radioisotope heat source capsules withinsaid container and spaced apart from each other and from walls of thecontainer for fluid flow therearound to heat said fluid, means forthermally insulating the radioisotope heat SOUISC capsules from thecontainer, first conduit means for transmitting said heated fluid fromthe interior of said container to said garment passageway and back tosaid container, pumping means for moving said fluid through said conduitmeans and container, a fluid bypass conduit means connected from saidfirst conduit means at a location in advance of entry into said garmentpassageway to said container for diverting heated fluid from the firstconduit means back to said container prior to entering said garmentpassageway and for cooling said fluid, and valve means for selectivelycontrolling movement of fluid through said first conduit means and saidbypass conduit means.

2. Apparatus as claimed in claim 1, wherein there is providedradioactivity shielding disposed intermediate the radioisotope and thethermal insulation means.

3. Apparatus as claimed in claim 1, wherein there is provided on saidcontainer a movable door for facilitating release of heat from thecontainer.

-4. Apparatus as claimed in claim 1, wherein said valve means includesaseparate valve in said bypass conduit for controlling fluid flowtherethrough.

References Cited UNITED STATES PATENTS 2,765,414 10/1956 Gendler et al17665 X 3,112,792 12/1963 Coleman et al 46 3,161,192 12/1964 McCormack126204 3,295,594 1/1967 Hopper 16546 FREDERICK L. MA'I'IESON, JR.,Primary Examiner.

E. G. FAVORS, Assistant Examiner.

